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Topic:Immunization
Immunization in horses involves the administration of vaccines to stimulate an immune response, thereby providing protection against specific infectious diseases. Vaccines commonly used in equine medicine include those for equine influenza, tetanus, and West Nile virus. The process of immunization aims to prepare the horse's immune system to recognize and combat pathogens upon exposure. Vaccination schedules and protocols may vary based on factors such as age, health status, and regional disease prevalence. This page compiles peer-reviewed research studies and scholarly articles that explore the mechanisms, efficacy, and considerations of immunization practices in equine health.
Detection and effects on platelet function of anti-platelet antibody in mule foals with experimentally induced neonatal alloimmune thrombocytopenia. Horse mares carrying mule foals were immunized during the last trimester of pregnancy with whole acid-citrate-dextrose-anticoagulated donkey blood to experimentally induce neonatal alloimmune thrombocytopenia. Thrombocytopenia occurred in the neonatal mule foals born to immunized horse mares within 24 hours after ingestion of their dams' colostrum. Mule foals born to mares not immunized with donkey blood did not develop thrombocytopenia. These findings suggest that antibodies may have been directed against a donkey platelet antigen present in the mule foals but not present in their dams. The o...
Vaccination against lyme disease with recombinant Borrelia burgdorferi outer-surface protein A (rOspA) in horses. Eight 1-year-old ponies were vaccinated with recombinant OspA (ospA gene derived from B. burgdorferi B31) with adjuvant (aluminium hydroxide). Four ponies were used as non-vaccinated controls with adjuvant. One hundred and twelve days after the first vaccination, the vaccinated and non-vaccinated ponies were challenged by exposure to B. burgdorferi-infected adults tick (Ixodes scapularis) collected from Westchester County, New York (tick infection rate >/=60%). Protection from infection was evaluated by culture for B. burgdorferi from three monthly skin biopsies taken near the site of tick bit...
BERNA: a century of immunobiological innovation. At the time the Swiss Serum and Vaccine Institute Berne (BERNA) was found in 1898, few vaccines or immune globulins were available. This short list included vaccines against cholera, typhoid fever, plague, smallpox and rabies and equine anti-tetanus and diphtheria immune globulins. Furthermore, their use was restricted due to limited production capacity, uncertainty regarding safety and no public health infrastructure to promote their utilization. Today, safe and effective vaccines exist for more than 30 infectious diseases while human hyperimmune globulins exist to treat or prevent rabies, te...
Evaluation of antibody parameters as potential correlates of protection or enhancement by experimental vaccines to equine infectious anemia virus. We previously demonstrated in trials of a variety of experimental vaccines to equine infectious anemia virus (EIAV) a remarkable spectrum of efficacy ranging from sterilizing protection to severe enhancement of virus replication and disease, depending on the immunization strategy used. This range of vaccine efficacy observed in vivo offers a unique opportunity for evaluating potential in vitro immune correlates of protection and enhancement. We describe here a comprehensive analysis and comparison of EIAV envelope-specific antibody responses elicited by attenuated, inactivated whole virus and ...
Potential of DNA-mediated vaccination for equine herpesvirus 1. The potential of DNA-mediated immunisation to protect against equine herpesvirus 1 (EHV-1) disease was assessed in a murine model of EHV-1 respiratory infection. Intramuscular injection with DNA encoding the EHV-1 envelope glycoprotein D (gD) in a mammalian expression vector induced a specific antibody response detectable by two weeks and maintained through 23 weeks post injection. Immune responses were proportional to the dose of DNA and a second injection markedly enhanced the antibody response. EHV-1 gD DNA-injected mice developed neutralising antibodies, and a predominance of IgG2a antibod...
[The effect of the essential fatty acids in mare’s milk on the function of the immune system and of nonspecific resistance in rats]. The influence of essential fatty acids of mare's milk fat on the immunocompetent system and nonspecific resistance of male rats weighing 135-145 g was investigated after 6 weeks of feeding. Rats were fed with isocaloric purified diets containing 15% of test fat (in control--combination of lard and sunflower oil) which provide the ratio of omega-6/omega-3 fatty acids equal to 0.76. An increase of immune responsiveness and nonspecific resistance in the group fed with the diet with mare's milk fat on day 6 after a single immunization of the animals with 5% sheep erythrocyte suspension was noted.
In vitro antibody-dependent enhancement assays are insensitive indicators of in vivo vaccine enhancement of equine infectious anemia virus. We have previously demonstrated a high propensity for enhancement of virus replication and disease resulting from experimental immunization of ponies with a baculovirus recombinant envelope (rgp90) vaccine from equine infectious anemia virus (EIAV). The current studies were undertaken to examine the correlation between the observed in vivo vaccine enhancement and in vitro assays for antibody-dependent enhancement (ADE) of EIAV replication. Toward this goal an optimized EIAV in vitro enhancement assay was developed using primary equine macrophage cells and used to evaluate the enhancement prope...
A particulate viral protein vaccine reduces viral load and delays progression to disease in immunized ponies challenged with equine infectious anemia virus. Immunization regimens that induce a broadly reactive cytolytic T lymphocyte (CTL) response specific for lentiviral antigens have emerged as the leading candidates in efficacy trials conducted in both animal modelshumans. To date, lentivirus vaccination strategies have overlooked one such immunization strategy, namely the use of particulate antigens. To evaluate the efficacy of targeting antigen into the phagocytic pathway to elicit a cell-mediated immune response to lentiviral antigens, we initiated the first study of a particulate-based vaccination protocol using a large animal model system. ...
Equine peripheral blood mononuclear cells proliferate in response to tetanus toxoid antigen. It has been reported that equine peripheral blood mononuclear cells (PBMNs) do not proliferate in response to tetanus toxoid (TT) (Frayne and Stokes 1995, Research in Veterinary Science 59, 79-81). Here we demonstrate that lymphocyte proliferation responses to TT, which are characteristic of a recall antigen, may be achieved under certain culture conditions. Given that TT vaccination is routinely applied to many horses, TT is a suitable antigen for the investigation of cellular immune responses by peripheral blood mononuclear cells in the horse.
Inhibition by CaNa2EDTA of local tissue damage induced by Bothrops asper (terciopelo) venom: application in horse immunization for antivenom production. The ability of the chelating agent CaNa2EDTA to inhibit local tissue damage induced by Bothrops asper venom was studied in mice and in horses used for polyvalent (Crotalinae) antivenom production. CaNa2EDTA was devoid of toxicity when injected i.m. or s.c. inducing only a mild edema. Preincubation of B. asper venom with CaNa2EDTA inhibited hemorrhagic and dermonecrotic activities, but did not reduce edema-forming and myotoxic effects. A group of horses initially immunized with native venoms developed less severe local tissue reactions when injected with booster doses of venom and CaNa2EDTA tha...
Immunization with a recombinant envelope protein (rgp90) of EIAV produces a spectrum of vaccine efficacy ranging from lack of clinical disease to severe enhancement. We have previously reported that immunization of ponies with a baculovirus-expressed recombinant surface unit envelope protein (rgp90) for equine infectious anemia virus (EIAV) resulted in enhancement of disease symptoms and virus replication in 4 of 4 vaccine recipients subjected to a heterologous virus challenge (rpg90 I vaccine trial) (Wang et al., 1994). To extend these studies of EIAV vaccine enhancement, two additional and independent rgp90 vaccine trials (rgp90 II and rgp90 III) were performed. Combined, a total of 13 ponies were immunized with the rgp90 immunogen using our standard vac...
Prevention of rotavirus diarrhoea in foals by parenteral vaccination of the mares: field trial. Many countries have reported rotavirus diarrhoea in foals. In Argentina it causes important economic losses to the horse industry. In this work we present the results obtained using an experimental vaccine in a farm with enzootic infection of rotavirus. A hundred mares were vaccinated 60 and 30 days before foaling with inactivated rotavirus SA11 (G3P2), H2 (G3P12), Lincoln (G6P1), with aluminum hydroxide as adjuvant; 65 mares were included in the unvaccinated, control group. To evaluate the vaccine, morbidity, duration of the diarrhoea and rotavirus shedding were recorded. Antibody levels were...
Affinity purification and characterization of a fibrinogen-binding protein complex which protects mice against lethal challenge with Streptococcus equi subsp. equi. Cell-wall-associated proteins from Streptococcus equi subsp. equi, the causative agent of strangles, were analysed with a view to identifying a potential protective antigen. Preparations of these proteins, isolated from mutanolysin extracts of cell walls, were shown to contain one major high-M(r) protein species (apparent M(r) 220,000 and 550,000 when analysed by SDS-PAGE and gel-filtration chromatography, respectively). The high-M(r) protein bound horse fibrinogen and was purified under non-denaturing conditions using fibrinogen affinity chromatography. The fibrinogen-binding protein (FgBP) r...
An outbreak of foal yersiniosis in Poland: pathological and bacteriological examination. In the springtime of 1995, 10 per cent of foals at a stud-farm died due to suppurative lesions. Three dead foals were examined. The manifestations of watery diarrhoea and pneumonia were observed. A profuse growth of an enterotoxigenic strain of Yersinia pseudotuberculosis was obtained from the internal organs of the foals. The foals with clinical symptoms of pneumonia and watery diarrhoea were immunized with Propionibacterium acnes t. II. All mares and their offspring from the stud were treated with an immunomodulator (Propionibacterium acnes t. II) and then vaccinated with a formalin-inactiva...
Interspecific and extraspecific pregnancies in equids: anything goes. Equids possess the unusual ability to interbreed freely among the phenotypically and karyotypically diverse member species of the genus to produce viable, but usually infertile, offspring. The mule (female horse x male donkey) was humanity's first successful attempt at genetic engineering and its clear expression of both parental phenotypes has contributed much to our understanding of genetic inheritance over the centuries. Even more surprising, mares and donkeys have been shown to be capable of carrying to term a range of true, xenogeneic extraspecies pregnancies created by embryo transfer, i...
Preliminary study of ovarian activity in fillies treated with a GnRH vaccine. To investigate the effects of two doses (200 and 400 mg) of a water-soluble gonadotrophin-releasing hormone vaccine on the ovarian activity of 2-year-old fillies. Methods: A controlled vaccination dose rate experiment. Methods: Six 2-year-old Australian Stock Horse fillies were randomly allocated to three treatment groups; unvaccinated controls, those receiving 200 mg of the vaccine and those receiving 400 mg of the vaccine. Results: Ovarian activity of the treated fillies was suppressed at the peak of breeding season while that of untreated controls continued normally. The control fillies dis...
Production of highly potent horse antivenom against the Thai cobra (Naja kaouthia). Naja kaouthia (NK) causes the highest fatality due to snake venom poisoning in Thailand. The specific antivenom produced is of low potency and in short supply. The aim of this study was to improve the antivenom potency. Bentonite and complete Freund's adjuvants (CFA) and various immunogens were compared. Six groups of three to five horses were immunized as follows: Group 1, NK venom adsorbed on bentonite; Group 2, NK venom in CFA; Group 3, NK venom in CFA in multi-emulsion formulation; Group 4, NK venom in 25% CFA; Group 5, NK neurotoxin 3 (NK3) conjugated with tetanus toxoid (NK3-TT) in CFA; ...
Field study of the safety, immunogenicity, and efficacy of an inactivated equine rotavirus vaccine. To determine safety, immunogenicity, and efficacy of an inactivated equine rotavirus vaccine. Methods: Prospective randomized controlled trial. Methods: 316 pregnant Thoroughbred mares during the first year of the study and 311 during the second year. Methods: During the first year, mares received 3 doses of vaccine or placebo, IM, at 8, 9, and 10 months of gestation. Serum neutralizing antibody titers were measured before vaccination and 1 and 35 days after foaling. Antibody titers were measured in foals 1, 7, 35, 60, 90, and 120 days after birth. During the second year, mares that had been v...
Immunogenicity and efficacy of baculovirus-expressed and DNA-based equine influenza virus hemagglutinin vaccines in mice. Two fundamentally different approaches to vaccination of BALB/c mice with the hemagglutinin (HA) of A/Equine/Kentucky/1/81 (H3N8) (Eq/KY) were evaluated, that is, administration of HA protein vs administration of HA-encoding DNA. Each vaccine was tested for its immunogenicity and ability to provide protection from homologous virus challenge. HA protein was synthesized in vitro by infection of Sf21 insect cells with a recombinant baculovirus. Intranasal administration of this vaccine induced virus-specific antibodies, as measured by enzyme-linked immunosorbent assay (ELISA), but did not induce ...
Antigenic analysis of Rhodococcus equi preparations using different horse sera. An R. equi vaccine, prepared under conditions which induce the expression of many antigens, and which has given encouraging results in field trials, was analyzed by SDS-PAGE and immunoblots and compared with other R. equi preparations: a preparation made in with the same technique from a nonvirulent isolate (virulence associated protein negative, VapA-negative); a whole cell preparation of a VapA-positive R. equi, prepared as a standard bacterin; and a semipurified VapA preparation (APTX). The antigens in these preparations were analyzed using hyperimmune sera (from adult horses vaccinated wit...
Immunoprophylaxis of Rhodococcus equi pneumonia in foals. An immunoprophylaxis program for R. equi infection of foals has been established on a number of thoroughbred breeding farms in Argentina over the past 4 years. Nearly 800 mares annually were immunized subcutaneously during the last 2 months of pregnancy with 2-3 doses of a vaccine containing soluble antigens of R. equi, including the virulence associated protein (VapA) and 'equi factors' exoenzymes. The mortality from R. equi pneumonia in the foals from vaccinated dams dropped from an average of 3% in the 5 years before the vaccination program was initiated to an average of 1.2% in the 4 years...
Protective effect against Rhodococcus equi infection in mice of IgG purified from horses vaccinated with virulence associated protein (VapA)-enriched antigens. IgG was purified from horses immunized with repeated doses of virulence associated (VapA) enriched antigens extracted with Triton X-114 from the surface of a virulent strain of R. equi. This IgG were administered to mice immunosuppressed by prior treatment with indomethacin. Mice administered the higher dose were completely protected against intraperitoneal infection with R. equi; mice given the lower dose were partially protected. By contrast, mice administered concentrated nonimmune equine IgG were not protected. This study demonstrates that VapA may be an important antigen involved in humor...
Tumor necrosis factor-alpha production and disease severity after immunization with enriched major core protein (p26) and/or infection with equine infectious anemia virus. Cardinal features of equine infectious anemia (EIA) include fever, hemolytic anemia and thrombocytopenia during the acute phase of the disease, and cachexia and anemia seen during the chronic phase. These signs are thought to result from the release of inflammatory cytokines such as TNF-alpha. In order to determine if TNF-alpha has a role in the pathogenesis of acute EIA and vaccine-induced disease enhancement, we measured plasma concentrations of TNF-alpha in ponies immunized with virus enriched major core protein-p26 and/or experimentally infected with EIAV. Naturally infected inapparent EIA...
Simulation studies of vaccination strategies in African horse sickness. A simulation model including two hosts (horses and donkeys) and one vector (Culicoides imicola) for African horse sickness in Spain is extended to consider vaccination strategies. If hosts were protected prior to virus introduction, elimination of simulated epidemics was related nonlinearly to the fraction protected. Protecting donkeys as well as horses increased the effectiveness of vaccination. Prevention of 50% of epidemics required 75% coverage of horses and donkeys or 90% coverage of horses only. Protection after the introduction of the virus was rarely successful in preventing outbreaks....
Use of Rhodococcus equi virulence-associated protein for immunization of foals against R equi pneumonia. To evaluate use of the virulence-associated protein of Rhodococcus equi in immunizing foals against R equi pneumonia. Methods: Eight (experimental group) and 6 (controls) mares with their foals. Methods: Virulence-associated protein extracted from R equi was used to prepare an acetone-precipitated. Triton X-extracted (APTX) antigen. After determination of the efficacy of passive immunization, in untreated foals or in foals given plasma from a horse vaccinated with APTX antigen or from a nonvaccinated horse, a field trial was done to evaluate the efficacy of vaccination of 8 mares, twice with A...
Clinical and laboratory alterations in horses during immunization with snake venoms for the production of polyvalent (Crotalinae) antivenom. Six horses were immunized with the venoms of Bothrops asper, Crotalus durissus durissus and Lachesis muta stenophrys for the production of polyvalent (Crotalinae) antivenom. During the immunization, clinical and laboratory alterations were evaluated in these animals, and the development of humoral immune response was followed. Only moderate local tissue changes (edema, abscesses, fistules and fibrosis) were observed in these animals, whereas no systemic alterations occurred. Regarding laboratory tests, there was a drop in hemoglobin concentration and hematocrit, together with an increment in t...
Use of a virulence-associated protein based enzyme-linked immunosorbent assay for Rhodococcus equi serology in horses. An enzyme-linked immunosorbent assay (ELISA) was developed against Rhodococcus equi using Triton X-114 detergent extracted whole cell material, in which the virulence associated protein (VapA) predominated. Enzymelinked immunosorbent assay titres corresponded to antibody reacting with VapA on Western blots. There was considerable variation in antibody titres of nonimmunised mares and in the time when the colostrally derived antibody of their foals had declined to low or undetectable titres. In general, antibodies in foals declined to their lowest levels at age 4-8 weeks. Seroconversion occurre...
Recombinant baculovirus-synthesized African horsesickness virus (AHSV) outer-capsid protein VP2 provides protection against virulent AHSV challenge. African horsesickness virus serotype 4 (AHSV-4) outer-capsid proteins VP2 or VP2 and VP5, prepared from single or dual recombinant baculovirus expression vectors grown in Sf9 insect cells, were administered in different amounts to horses and the neutralizing antibody responses were measured. Control and vaccinated horses were challenged with virulent AHSV-4 6 months later and monitored post challenge. The results indicated that two inoculations of extracts containing VP2 and VP5, or VP2 alone, in doses of 5 micrograms VP2 or more per horse, were sufficient to elicit protection against African ...
